Water microbial disinfection via supported nAg/Kaolin in a fixed-bed reactor configuration

• Published in: Applied clay science 2020-01, Vol.184, p.105387, Article 105387
• Main Authors: Ozer, Lütfiye Yıldız, Yusuf, Ahmed, Uratani, Joao M., Cabal, Belén, Díaz, Luis A., Torrecillas, Ramón, Moya, José S., Rodríguez, Jorge, Palmisano, Giovanni
• Format: Article
• Language: English
• Subjects: Fixed-bed reactor; Kaolinite; Kn/nAg composites; Silver nanoparticle; Water microbial disinfection
• ISSN: 0169-1317; 1872-9053
• DOI: 10.1016/j.clay.2019.105387

In this paper we have investigated and demonstrated the antimicrobial capabilities of nano-silver-4 wt%-kaolin (nAg-4-Kn) composite supported on borosilicate glass beads (BGB). Tests have been conducted in a fixed bed reactor on effluent from the secondary clarifier of a conventional wastewater treatment plant (WWTP) in Abu Dhabi, United Arab Emirates (UAE). The prepared BGB with immobilized nAg-4-Kn (nAg-4-Kn/BGB) were characterized using the RAMAN spectroscopy, TEM equipped with EDX and Focus Ion Beam Scanning Electron Microscope (FIB-SEM) techniques. The rate of disinfection was assessed through Luria-Bertani (LB)-agar plate cell counting technique. The results showed complete disinfection after few hours, which was preserved even after several days in repeated runs. The nAg-4-Kn/BGB was reused, demonstrating that the immobilization of nAg-4-Kn was stably achieved, and the activity and integrity of the composites on the BGB were preserved. First order disinfection kinetic constants were estimated to be 2.76 cm h−1 and 2.56 cm h−1 in two consecutive runs. Analyses of the beads after the experiments showed minor losses of nAg from the kaolin matrix thereby corroborating reusability of these materials. •nAg/Kaolin composites supported on glass have significant antimicrobial properties.•Disinfection of a real effluent follows first order kinetics.•nAg/Kaolin composites are stably supported on glass beads.•nAg/kaolin supported on glass can be reused over a long time.